A 10th-minute red card for Josh Dasilva following a horror tackle of Matt Targett swung the game in Eddie Howe side’s favour.
Joelinton headed the Magpies in front on 33 minutes before Joe Willock extended the lead not long later.
While the Bees, boosted by a return to football for Christian Eriksen, pushed in the second-half but United held out fairly comfortably.
The three points lifts Newcastle above their hosts into 14th, four points above the Premier League relegation zone.
Here’s our writer Jordan Cronin’s player ratings from the victory at the Brentford Community Stadium.
While the Bees, boosted by a return to football for Christian Eriksen, pushed in the second-half but United held out fairly comfortably.